Glycine-β-Cyclodextrin–Enhanced Electrokinetic Removal of Atrazine from Contaminated Soils

Abstract

Abstract

Glycine-β-cyclodextrin (G-β-CD) was synthesized by the reaction of β-CD with glycine in the presence of KOH and epichlorohydrin. G-β-CD–enhanced solubilization and desorption behavior of atrazine were investigated, and the feasibility of using G-β-CD in electrokinetic (EK) removal of atrazine from contaminated soil was evaluated for the first time. Bench-scale EK tests were conducted under a voltage gradient of 2.0 V cm⁻¹ for 10 d, and deionized water, 0.05 M Na₂CO₃/NaHCO₃ buffer solution, 0.05 M Na₂CO₃/NaHCO₃ buffer solution containing 2 g/L G-β-CD and 0.05 M Na₂CO₃/NaHCO₃ buffer solution containing 10 g/L G-β-CD were used as anodic flushing solutions, respectively. Results from solubilization experiments showed that the solubility of atrazine in 30 g/L of G-β-CD was enhanced about 4.2-fold. Desorption efficiency of atrazine in soil increased with increasing G-β-CD concentration. Experimental results from EK remediation tests showed that migration and removal of atrazine in soil were significantly affected by G-β-CD concentrations and cumulative electroosmotic flow. pH control is beneficial for migration and removal of atrazine. In a test with deionized water (E1), only about 4.4% of atrazine was removed from the soil near the anode, whereas 12% of atrazine was removed using the deionized water test with pH control (E2). When G-β-CD was added to anodic flushing solution, the 2 g/L and 10 g/L G-β-CD flushing solution showed approximately 33% and 40% removal, respectively. The EK process combined with G-β-CD flushing and pH buffering may be a good remediation alternative for hydrophobic organic contaminant removal from contaminated soil.